渠道边壁糙率变化对其输水能力影响研究

Study on Influence of Variation of Channel Side Wall Roughness to the Water Carrying Capacity

为探讨渠道边壁糙率变化对渠道输水能力的影响,采取不同加糙体布置形式对梯形渠道进行加糙,通过河工模型试验分析渠道内断面的垂线流速、壁面切应力以及摩阻流速的变化规律。结果表明:受边壁糙体阻碍作用的影响,靠近渠道边壁的垂线流速较小,中垂线流速大于两侧垂线流速;壅水造成最大流速出现在水面以下;当糙体间距和尾门开度一定时,整体上摩阻流速和壁面切应力随着流量的增大而增大;当尾门开度和流量一定时,糙体间距越小,摩阻流速和壁面切应力越大。

In order to explore the effect of channel wall roughness change on the channel water transport capacity,different roughening bodies were used to roughen the trapezoidal channel.The variation law of vertical velocity,wall shear stress and friction velocity in the channel section was analyzed through the river engineering model tests.The results show that affected by the obstruction of the rough body on the side wall,the vertical velocity near the side wall of the channel is smaller,the velocity in the middle vertical is greater than that on the two sides.The backwater causes the maximum flow rate to appear below the water surface.When the rough body spacing and the opening of the tailgate are constant,the overall frictional flow velocity and the wall shear stress increase with the increase of the flow rate.When the opening of the tailgate and the flow rate are constant,the smaller the roughness spacing,the greater the frictional flow velocity and wall shear stress.